Capacitive reactance is equal to _______. 

CONCEPT:

• A circuit that has the only capacitor is known as a purely capacitive circuit.

EXPLANATION:

• Capacitive reactance is defined as the resistance offered to the flow of current by the capacitor.
  • It is denoted by letter XC.
• The capacitive reactance is given by:

\(\Rightarrow{X_c} = \frac{1}{{\omega C}} = \frac{1}{{2\pi ν C}}\)

Where C = capacitance and ν = supply frequency

• Capacitive reactance is inversely proportional to the supply frequency, i.e.

\(\Rightarrow {X_c} \propto \frac{1}{{ \nu}}\)

• If the frequency increases, the capacitive reactance decreases and vice-versa.
• Alternating emf in the circuit is
  \(e = {e_o}\sin \omega t\)
• Current in the inductive circuit is –
  \(I = {I_o}\sin \left( {\omega t + \frac{\pi }{2}} \right)\)
• From above it is clear that current leads the voltage by π/2.